Microwave-free wide-field magnetometry using nitrogen-vacancy centers

A wide-field magnetometer utilizing nitrogen-vacancy (N-V) centers in diamond that does not require microwaves is demonstrated. It is designed for applications where microwaves need to be avoided, such as magnetic imaging of biological or conductive samples. The system exploits a magnetically sensitive feature of N-V centers near the ground-state level anticrossing (GSLAC). An applied test field from a wire has been mapped over an imaging area of ≈500×470μm2. Analysis of the ground-state level anticrossing (GSLAC) lineshape allows us to extract the vector information of the applied field. The device allows micrometer-scale magnetic imaging at a spatial resolution dominated by the thickness of the N-V layer (here, 50μm). For a pixel size of 4μm×3.8μm, the estimated photon-shot-noise-limited sensitivity is 4.8μT/Hz. Two modalities for visualizing the magnetic fields, static and temporal, are presented, along with a discussion of technical limitations and future extensions of the method. © 2024 American Physical Society.